Download Assistant doesn't work on Mac OSX 10.11.2

When I start the Unity Download Assistant, the icon shows up but nothing happens.

This is what it says when I run it from terminal:

Klavs-MacBook-Pro:Unity Download Assistant klavs$ Unity\ Download\ Assistant.app/Contents/MacOS/Unity\ Download\ Assistant 2015-12-21 16:33:48.385 Unity Download Assistant[60412:570151] Failed to connect (customSheet) outlet from (AppDelegate) to (NSPanel): missing setter or instance variable 2015-12-21 16:33:48.861 Unity Download Assistant[60412:570151] *** -[__NSArrayM objectAtIndex:]: index 18446744073709551615 beyond bounds [0 .. 2]

I tried multiple Download Assistant versions with no luck.